New engine - Any tips now that it sucks?

[Dave]

I've put about 200 miles on the new engine. It was rebuilt about 6 years ago, I think Christian put about 10,000 miles or less on it over that time. He re-ringed it and put new rod bearings in about 190 miles ago. So I got it with 10 miles on the rings and rod bearings. I tried to break it in per Motoman's direction. I pulled the plugs and noticed a good deal of carbon buildup on all 4 cylinders... cyl 1 and 2 seem "wet" though. This was while the engine was hot still. Compression test seemed a bit "high" at 150psi across the board.

So it appears the rings have sealed, however, the oil looks very dirty. I changed it at 50 miles, and just checked it today. It looked almost 2,000 miles old. It was also a whole quart low. Breather seems to be working quite a bit as well...

The biggest issue though is that the engine breaks up at higher RPMs. I first noticed this at about 100 miles as I was boosting along. The narrowband danced back and forth from rich to lean and acted is if was a 2 step, cutting the fuel. I later noticed it's RPM related. Today I noticed it at only 3,700 RPMs. On my way to my paren'ts I noticed it at 3,500 RPMs. On my way home noticed it at 3,000 RPMs and slightly stumbling at part throttle around 2,800 RPMs.

The fuel did sit for 6 years. I added a few gallons of new 93 octane before after the first startup. I just filled it up, and have gone through a 1/4 tank already.

I'm thinking clog in the fuel system? I replaced the hall effect with another one, cleaned the rotor, cleaned the plugs and regapped to .031". Could also be a coil,cap, or wires I suppose. But I really think it's fuel related.

Any thoughts on these 2 issues?

Thanks!

Oh, I took a video of the stumbling issue. First part is under load at about 5 psi on the highway, last try is with 0-1psi and just throttle it to show the RPM.

[Ubmbass]

WOW 6 year old fuel? and you're wondering why you are having trouble? haha.. You need to drain all that old crap out and flush the fuel lines and start fresh.. especially if you plan on running any sort of power..

[zin]

I hate to say it, but if you have "wet" black plugs, lots of "goo" in the breather and are a quart low in short order... Well, that sounds like rings to me, like they went in new on a worn/slick cylinder and couldn't seat, so they are letting oil up into the chamber and combustion gases into the crank case, belching oil mist into the breather... The miss would be the plugs fouling with oil.

Try putting in some fresh plugs and see if that doesn't fix the miss. If I'm right, it'll be good for awhile, then come back in pretty much the same fashion you became aware of it.

The comp test would show a bit better than expected if there was oil in the rings/chamber, that's one of the ways you check for bad rings, adding a teaspoon of oil in the spark plug hole, then re-test, if it goes up, bad rings...

Hopefully I'm wrong and it's something easier to fix, but that's not what my gut tells me...

Mike

[Dave]

WOW 6 year old fuel? and you're wondering why you are having trouble? haha.. You need to drain all that old crap out and flush the fuel lines and start fresh.. especially if you plan on running any sort of power..

lol I thought it would gel up a little. In fact I didnt expect it to start, but once it did I figured all was well. Especially since it drove around fine for the first 50 or so miles. I may replace the filter, unplug the feed line, make sure it's flowing clean, check the pressure, and clean the injectors and rail. If I have to drop the tank that will have to wait for winter time.

[glhs727]

check your fuel pressure when the stumble happens. If you had 6 year old gas in the tank, you probably had crap in the tank too. Your fuel pump may have sucked up some debris and now is going or has gone bad.....

[RoadWarrior222]

Yeah or there's flakes of "varnish" randomly blocking the injector jets before they break up or re-dissolve.

[shadow88]

Yeah or there's flakes of "varnish" randomly blocking the injector jets before they break up or re-dissolve.

Injectors and rail would be where I would turn after flushing the tank.

[turbovanman²]

Change the fuel filter if you haven't. Change the plugs. Run new gas.

To diagnose oil burning-

http://www.turbo-mopar.com/forums/vb...&articleid=180

[audiomaninc]

or a severely noisy valvetrain causing the knock sensor to pull a chit load of timing?

[Five9dak]

Wow the gas in my car looked horrendous after 2 years. Even using a few gallons of it on top of half a tank of 93 in other cars made them ping like mad when we tried to burn it off.

[Dave]

I've been taking it easy since the gas is old and I don't have a knock sensor wire hooked up yet. Should be here today, we ordered one. Thanks for all the help guys. Ill grab a Summit fuel filter (maybe a 10 or 35 micron), clean the rail and injectors and test the fuel pressure.

[Dave]

40 micron... we'll see how it does.

http://www.summitracing.com/parts/SUM-230100/

[RoadWarrior222]

Even using a few gallons of it on top of half a tank of 93 in other cars made them ping like mad when we tried to burn it off.

Yup, it's the lighter stuff, that is the higher octane component that will evaporate off, leaving the low octane stuff behind. I always like to stick a bottle of isopropyl alcohol per half tank or part of in anything that's been sitting.

I had a big can of drain-off that was a year old, 2 years ago, that I was using for my mower and kept sticking cupfuls of isopropyl and methanol in it every so often. Just finally finished it... managed to run the mower fine... ran the tank dry at the beginning of Sept, just needed a final cut again now, so went and got fresh gas... kind of expecting the mower to run different or be easier to start or something. (Takes 3 priming pulls, no primer bulb on it) ... nope, sounded normal.

I had 3/4 tank when I killed my Escort HG and it sat for damn near 2 years before I could get it fixed, stuck about a pint of iso and a pint of methanol in it to fire it up... and I had to get an e-test right away, didn't have time to run the old out... ran fine, passed fine.

[Dave]

Guess what?



All better now! Revs all the way to 6,000 at 7psi!

Thanks again for all the help guys.

[3Bar_Mopar]

Yeah...I don't know about using that filter....the link you posted said the filter is rated at 130 GPH and for carb use.

"Designed for carbureted systems, our filters flow 130 gph and have a reusable 40-micron element. Each 4.00 in. long filter is machined from aircraft-quality billet aluminum. They're available in red, blue, or black anodized or polished finishes with -6 AN or -8 AN fittings."

[Dave]

That is a general description they use. You'll find descriptions like that on the website on lots of parts. This one is rated at 70psi. It's the lazy data department that doesn't use accurate descriptions.

[RoadWarrior222]

I thought our pumps went higher than 70...

[Dave]

They can but the pump only produces around 45-50psi at the rail, depending on your FPR settings. Generally when you go to larger injectors the base pressure goes down. So if I we're running a base of 40psi + 30psi boost reference then I'm still fine. If my base we're higher than that then I'd be in trouble. I'll always keep that account in my head as I turn the boost up and dial in my fuel pressure.

Also, to be totally honest if you we're to go much higher than a 50psi base pressure, you're either 1) Making up for small injectors by running higher pressure, so buy bigger injectors, or 2) You're running out the pump, buy a larger capacity fuel pump. The more pressure ahead of a pump the less it will flow in lbs/hr.

[RoadWarrior222]

But it's only regulated at the rail, the excess is bled off on the return line. The supply line is higher pressure than the rail.

[Dave]

But it's only regulated at the rail, the excess is bled off on the return line. The supply line is higher pressure than the rail.

Right, that pressure traps the fuel all the way back at the source though, ie, the pump. The return line I don't believe sees any pressure.

So in our example, 40psi base + 30psi 1:1 boost ref. sets the total feed line pressure at 70psi.